The goal of the proposed research is to examine in nonhuman primates the environmental and pharmacological factors involved in the control of behavior by nicotine. One series of stuies will establish a profile of the behavioral effects of nicotine by determining its effects on performance maintained by various consequent events (e.g., delivery of food or electric shock) under several schedules of reinforcement (e.g., fixed-interval and fixed-ratio schedules; schedules involving both reinforcement and punishment). These experiments will: 1) compare directly the effects of nicotine with those of related nicotinic agonists (e.g., cotinine; nornicotine; lobeline) and psychomotor stimulants (e.g., amphetamine; cocaine); 2) examine the interactions between nicotine and drugs that may either antagonize (e.g., mecamylamine; atropine) or potentiate (e.g., physostigmine) the effects of nicotine; and 3) assess the development of tolerance to effects of nicotine. A second series of studies will determine the conditions under which intravenous injections of nicotine function as reinforcers or punishers. The development and maintenance of behavior will be examined using schedules (e.g., fixed-interval, fixed-ratio and second-order schedules) in which responding produces injections of nicotine. The suppression of behavior will be examined using schedules in which responding produces both the delivery of food and the injection of nicotine. Techniques for maintaining alternative behaviors that result in a decreased frequency of nicotine self-administration will also be studied. The conditions under which nicotine either maintains or suppresses behavior will be studied systematically, and the resultant performances will be compared with those maintained or suppressed by other events, including the injection of other drugs, to establish similarities and differences between nicotine and other events that can function as reinforcers or punishers. Drugs that antagonize or potentiate the action of nicotine will be studied on behavior maintained or supressed by nicotine injection. The results of this research should provide an experimental model of the diverse effects of nicotine use in man.